Pantograph



3 Sheets-Sheet 1.

(No Model.)

W.-E. HOKE.

. PANTOGRAPH.

Patented Feb. 20, 1894.

. n v m e e.

Zwawvraa (No Model.) 3 SheetsSheet 2.

W. E. HO'KE'.

PANTOGRAPH. I No. 514,992. Patented Feb. 20, 1894.

(No Model.) v 3Sheets- -Sheet ,w. E. HOKE.

I PANTOGRAPH. No. 514,992. f Patente'dFeb. 20,1894.

Unwrap PATENT PANTOGRAPH.

SPECIFICATION forming part of Letters Patent No. 514,992, dated February20, 1894.

Applicationfiled August 26, 1892. Serial Nn.444,233. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM E. HOKE, of St. Louis, Missouri, have made anew and useful Improvement in,Pantographs, of which the following is afull, clear, and exactdescription.

The improvement relates more especially to the construction of thejoints of the instrument, and to thennode of supporting the free-' endportion of the instrument, substantially as is hereinafter set forth andclaimed, aided Fig. 4; Fig. 6 a plan of the top-plate ofthe clamp usedfor an adjustable joint; Fig. 7 a vertical section on theline 77 of Fig.6;

Fig.8 a plan of the bottom-plate of the clamp;

Fig. 9 a side elevation of thebottom plate of the clamp Fig. 10 adetail, being a vertical section of one of thejoints of the ends of thebars; Fig. 11 adetail, being an elevation of the pencil or cuttingpointholder in position in its bar which is shown in section; Fig. 12 adetail, being an elevation of the bearing-point'in position in its barwhich is shown in section; Fig. 13 a view analogous to that of Fig. 7,but showing aspecial arrangement of the set screw, a feature of theimprovement: and'Fig. 14 a view analogous to that of Fig. 6, a por-.tion of the clamp being broken away, and the set screw having thespecial arrangement referred to.

The last twelve named views are upon an enlarged scale.

The same letters of reference denote the same parts. i

A, B, O, D, respectively represent the bars of the instrument. The barsA and B are jointed together at a, and the bars 0 and D at c. The barsAand C are jointed together bymeans of the clamp E, and the barsB and Dby means of the clamp E. The fulcrum is at F, and the bars B, O, arerespectively, adapted to carry a tracer G, and a pencil orcutting-point, H, or other operating tool, and

said bars may each be perforated, as at 0', to receive a bearing-pointI, and, saving as the instrument is supplemented or modified by theimprovement under consideration, it is of the customary construction andoperation.

J represents an elevated bearing arranged over the fulcrum, and atasuitable height for its purpose. It is preferably the notched upper endof the post j whose lower portion forms the fulcrum of the instrument.

K represents a tiein practice a cord connected with the instrument atits joint a, and.

leading thence to the bearing J,and, by bein g drawn sufficiently tight,serving to uphold the bars A B, at the outer end thereof, to enable theouter, free, portion of the instrument to swing clear of anysupportingsurface, any Work thereon, or other object which, otherwise, mightfrictionally retard the free movement of that portion of the instrument.The cord is conveniently held thus tightby stretching it' over thebearing J and securingits end, K,.to the screw or other projection, It,substantially as shown.

The post and projection may be held in any suitable support or supports,but, to more fully carry out the improvement, a special support, L,therefor, such asa block of wood of the shape shown, is provided which,in turn, is adapted to befastened removably or otherwise, to anysuitable sub-support, for instance the table-top or whatever surface, M,is sustaining the work being operated upon.

The post, j, is desirably secured in the block by confining it in aperforation, Z, therein, and as follows: The fulcrum, F, is formed bytapering the post as shown, and, below .said

fulcrum, the post is threaded atj', and the threaded portion is providedwith the nuts'j and 9' the bar, A, has a tapered perforation, a, toenable the bar to be passed onto and fit the fulcrum, and the bar isproperly adjusted upon the fulcrum to swing horizontally thereon, butwithout lost motion, by means of the nut j which is screwed upward onthe portion j of the post until the bar is suitably elevated and fittedto the fulcrum: the bar thus rests upon the nutj and the parts areproperly tightened in position in the block L by means of the outer nut,7' which is screwed upward upon the lower part of the portion 7' of thepost to'cause the nuts fig, to bindv uponthe top and bottom parts of theblock.

By this means an improved fulcrum is obtamed for the instrument and itsfreedom of movement upon the fulcrum facilitated.

The adjustable joints of the pantograph, namely the clamps, E, E, areconstructed as follows: In the place of perforating the pantograph barsand jointing the bars A and 0 together, and the bars B and 0 together,by p1ns,or analogous means, inserted in the perforat ons, I employ aconstruction which substantlally encircles or more or less embraces thetwo bars. Each clamp comprises what may be termed the bottom-plate, e,the topplate e, and the centering-point 6 together with suitable means,such as the set screws 6 e, for binding the plates to their respectivebars at the desired points thereon. The bottom-plate e is recessed at 6to be applied,from beneath it, and receive the under bar of the pair ofthe bars so that the bar can be slipped longitudinally therein, and ithas, or is extended to form, an arm, a which, when the bars A and O, orB and D, are put together, overhangs the upper bar at the center of thecrosslng of the bars. The top-plate, e, is recessed in its under side,as at e, to be passed downward onto the upper bar of the pair so that itcan be slipped longitudinally upon the bar. The two plates can, asstated, be re spectively clamped to the under and upper bars by means ofthe set-screws e 6 It is poss ble to arrange said set-screws as shown inFlgs. 6 and 7. But, owing to the shallowness of the recess in the plate,and to the desn'ableness of the two bars, in operation, bemg adapted tobe swung well around upon each other, I prefer to arrange the set-screwsin their plates substantially as is shown in Figs. 13 and 14; that is,slantingwise both vertically and horizontally so as to bring the head ofthe screw into position to clear the other bar, and at the same time toenable the point of the screw to be presented to the bar so that thebevel, c of the screw point shall bear sidewise against the bar-edge, bywhich means the bar can be bound without urging it out of its seat inthe plate: that is, with the screw slanting downward, there is atendency to force the bar out of its proper position in the plate, butwhen the horizontal slant is also used the turning of the screw to theright (as shown in Fig. 14) tends to correct the described influence ofthe other force, and the bar remains in its proper position. Thecentering-point, e when screwed down in the arm 6 enters the seat 6 inthe top-plate, and the jam-nut 6 serves to secure the point after it hasbeen vertically adjusted.

The graduations, or other guide-marks, N, N, upon the bars fordetermining their proper relative position may be as shown, or of anysuitable character.

The clamp has a suitable mark, 72, which, when registering with theneeded mark in the graduation, determines the location of the clamp uponthe bars. In this manner the bars of a pan tograph can be made of adesirable size, and be firmly, but easily, adjustably held. The bars canalso be adjusted to smaller difierences of graduation than if the barswere connected by a pin-and-perforation construction.

The mode of jointing the bars A and B together, and the bars 0 and D, isshown in Fig. 10: a bolt 0 having a cone-bearingo for one of the barspasses through that barsay the bar A, which has a correspondingly-shapedperforation to fit said bearing, and then through a perforation in theother bar B, and by means of the nut o the two bars are drawn together,and owing to the described cone-bearing the bars can be adjusted tosuitably turn upon each other without any lost motion in the joint. Thebearingpoint, which serves its usual purpose, is threaded to workthrough the bar, and, when adjusted therein, is secured by means of thejam-nut. The pencilorcutting point is similarly held and secured in itsbar.

The present instrument is well adapted for use upon chalk-plates such asshown at P, Fig. 1, and the cutting-point mentioned is suited for suchwork.

The tracer, in the use of the instrument, is moved in the usual mannerover the design, Q, to be copied, and the plate, P, is scoredaccordingly.

I claim- 1. In a pantograph, the combination of the support L,perforated at l, the post j, placed in said perforation, and having atapering portion fulcrumed in the perforated bar A, and screw threadedin the portion fitting in the perforation Z, and held in position by thenuts j, j substantially as described.

2. In a pantograph the combination of the lower clamp plate 6, recessedat 6 and the overhanging arm a the upper plate a, recessed at e, on itsunder side, and socketed at a and the centering point 6 adapted to besecured by jam nut a", substantially as described.

3. In a pantograph, in combination one of the bars, suitably perforated,the perforated support, the post tapered at its end and fulcrumed in thebar, and screw threaded below said bar and held in position in thesupport by nuts on said threads, substantially as specified.

4. In a pantograph, the combination with the pair of bars, as described,the clamp E, having bottom and top plates, as described,

the centering point 6 adapted to be moved in the arm 6 of said clamp andbe held in position,and the screws 6 ,6, for binding the plates to saidbars at the desired point thereon, substantially as described.

Witness my hand this 11th dayof July, 1892.

C. D. MOODY, B. F. REX.

